Anna Kendrick's outlook on sex messed with her head until she became open about it.

The Pitch Perfect actress is known for her outspoken nature and little is out of bounds, especially when it comes to her personal life.

In her new book, Scrappy Little Nobody, Anna writes candidly about her previous relationships and love life, though it took her some time to feel comfortable enough to share her experiences.

"That section about sex, I felt, 'Oh boy, I’m opening myself up here.' Once you talk about sex candidly, people might expect you to do it all the time," she sighed to U.S. Vogue magazine, as she explained how much it bothered her when women were criticized for sleeping with a number of men, yet when a man does the same he is considered a "stud". "I was like, 'What am I supposed to do?' Literally six months ago, I was humiliated that I hadn’t even had sex yet, and suddenly, I’m like, what if I have sex with too many people? How am I both things? How am I too inexperienced, and, to someone else’s eyes, too experienced? It really messed with me."

Now the 31-year-old's surrounded by positive people who are "sensitive and intelligent", the Up in the Air star no longer feels the same anxieties. However she knows other women do, and hopes that by sharing stories from her own life, as glamorous as it may seem from the outside, it will help others not to feel so alone.

"You have to make your mistakes, learn your life lessons," Anna explained. "But hopefully if you do make the same kind of mistakes, you don’t feel as bad because you know at least one other person has made them."

Scrappy Little Nobody is available to buy now.